Abstract: The invention relates to a temperature-independent voltage reference circuit. The circuit comprises a first circuit of bandgap type providing a first-order temperature-stable voltage, on the basis of a bipolar transistor base-emitter voltage having a negative slope of variation as a function of temperature, and of a voltage or a current having a positive slope of variation as a function of temperature provided by a generator of current proportional to absolute temperature. The base currents of the PMOS transistors thereof are compensated in such a manner that the output current is proportional to a collector current and not an emitter current.

Abstract: The invention relates to the fabrication of integrated circuits in general, and notably the circuits of image sensors intended to form the electronic core of photographic apparatus or cameras. The chip is first aligned with respect to the package and then the package is aligned with respect to the optical system. The alignment of the chip with respect to the package is done optically. The alignment of the package with respect to the system is done mechanically with respect to the edges of the package. According to the invention, provision is made for optical marks to be provided on the package, these marks each having an edge aligned with a lateral edge of the package, so as to minimize the positioning errors which would be due to inaccurate positioning of the chip with respect to the edges of the package.

Abstract: The invention relates to dental radiological image sensors for intraoral use. What is described is a method of fabricating an image sensor, comprising steps for the collective production of a structure combining a semiconductor wafer (12), bearing a series of image detection circuits, and a fiber-optic plate (20) fixed to one face of the wafer, the semiconductor wafer being thinned in a step subsequent to the formation of the image detection circuits on the wafer, and external access contact pads (28) are produced on that face of the wafer which is not fixed to the fiber plate, said contact pads being for controlling the circuits and for receiving image signals coming from the sensor, the fiber-optic plate having a thickness such that it provides most of the mechanical integrity of the structure once the wafer has been thinned, and to do so right to the end of the collective fabrication, the assembled structure consisting of the wafer and the plate being subsequently diced into individual chips.

Abstract: The invention relates to the collective fabrication of superposed microstructures, such as an integrated circuit and a protective cover. Individual structures each comprising superposed first and second elements are fabricated collectively. The first elements (for example, integrated circuit chips) are prepared on a first plate and the second elements (for example, transparent covers) are prepared on a second plate. The plates are bonded to each other over the major portion of their facing surfaces, but with no bonding of the defined zones in which there is no adhesion. The individual structures are then diced via the top on the one hand and via the bottom on the other hand along different parallel dicing lines passing through the zones with no adhesion, so that, after dicing, the first elements retain surface portions (those lying between the parallel dicing lines) that are not covered by a second element. A connection pad may thus remain accessible at this point.

Abstract: The invention relates to image sensors in the form of a signal-integrating, travelling multi-line linear array for the synchronized readout of one and the same linear image successively by N lines of P photosensitive pixels and the pixel by pixel summation of the signals read out by the various lines. At the start of a photogenerated-charge integration time, the output voltage of a pixel of a previous line of rank i?1 is applied to the photodiode of the pixel of an intermediate line of rank i, the photodiode is isolated, the charges due to light are integrated therein and, finally, at the end of the integration time, the charges of the photodiode are transferred to a storage node of the pixel. A charge-voltage conversion circuit transforms the charges of the storage node into an output voltage of the pixel.

Abstract: The invention relates to the fabrication of thinned substrate image sensors, and notably color image sensors. After the fabrication steps carried out from the front face of a silicon substrate the front face is transferred onto a substrate. The silicon is thinned, and the connection terminals are produced by the rear face. A multiplicity of localized contact holes are opened through the thinning silicon, in the location of a connection terminal. The holes exposing a first conductive layer (24) are formed during the front face steps. Aluminum (42) is deposited on the rear face, in contact with the silicon, with the aluminum penetrating into the openings and coming into contact with the first layer. The aluminum is etched to delimit the connection terminal. Finally, a peripheral trench is opened through the entire thickness of the silicon layer, and this trench completely surrounds the connection terminal.

Abstract: The invention relates to analog integrated electronic circuits using differential pairs. The proposal is for a method of automatic correction of offset voltage. The inputs (V1, V2) of the differential circuit are short circuited during a calibration phase distinct from the normal usage phase. A capacitor is charged through the difference of the output currents of the branches of the differential pair in this phase. The voltage at the terminals of the capacitor is compared with at least one threshold. During the normal usage phase following the calibration phase, the result of the comparison is kept in memory. In the normal usage phase, a correction is applied depending on the result kept in memory to a current source of a follower stage upstream of the differential pair.

Abstract: The invention relates to dental radiological image sensors for intraoral use. What is described is a method of fabricating an image sensor, comprising steps for the collective production of a structure combining a semiconductor wafer (12), bearing a series of image detection circuits, and a fiber-optic plate (20) fixed to one face of the wafer, the semiconductor wafer being thinned in a step subsequent to the formation of the image detection circuits on the wafer, and external access contact pads (28) are produced on that face of the wafer which is not fixed to the fiber plate, said contact pads being for controlling the circuits and for receiving image signals coming from the sensor, the fiber-optic plate having a thickness such that it provides most of the mechanical integrity of the structure once the wafer has been thinned, and to do so right to the end of the collective fabrication, the assembled structure consisting of the wafer and the plate being subsequently diced into individual chips.

Abstract: The invention relates to current switches using a differential pair of transistors and being able to operate under a low supply voltage Vcc. According to the invention, provision is made for the current switch to include two differential pairs of two transistors each (T1, T1b; T2, T2b), cascaded together, the second pair (T2, T2b) having complementary current outputs (H, Hb) that flip according to the states of the inputs (E, Eb). The first pair (T1, T1b) is connected to a ground (GND) through a current source, supplying a current of value Io and comprising a transistor (Ts1) biased by a voltage Vbias, and it is supplied by a voltage equal to N·Vbe+Vbias, where N is a whole number (preferably equal to 1) and Vbe is the base-emitter voltage of the transistor (Ts1). The second pair (T2, T2b) is connected to ground directly through a resistance (R2). The invention can be applied to the on-off control of sample-and-hold circuits, multiplexers, fast low-voltage logic circuits, etc.

Abstract: The invention relates to circuits for managing differential voltages in series. To individually control the differential voltages of voltage sources in series, there is provided an integrated control circuit for a set of N sources in series. This circuit comprises N discharge control and measurement cells which are each produced in a separate well, insulated from the substrate and from the other wells. The cells are linked to the circuits formed in the substrate by level translation circuits having a part inside the well and a part outside the well. These circuits use transistors withstanding voltages of several tens of volts. The integrated circuits may be cascaded on an SPI bus if one wishes to control a group of k.N sources with k>1.

Abstract: The invention relates to integrated circuits comprising a set of identical differential pairs of two transistors each (T1, T2; T3, T4) one receiving a variable voltage (Vinp, Vinn) at its base and the other receiving a fixed reference voltage (Vrefp, Vrefn). In order to reduce the dispersion of the offset voltages of said differential pairs, it is provided that the transistor (T2, T4) that receives a fixed reference voltage has an emitter surface at least twice as large as the transistor (T1, T3) that receives a variable voltage at its base. Application to signal folding circuits and to analog-to-digital converters using differential pairs of transistors.

Abstract: The invention relates to intraoral radiological dental image sensors, i.e. ones placed in a patient's mouth, an X-ray source being placed outside the patient's cheek in order to emit X-rays in the direction of the sensor. According to the invention, the sensor comprises a light source which is modulated by the collected radiological image information, in order to transmit the information optically. The light source, placed inside the patient's mouth, is preferably placed facing an optical fiber which emerges from the mouth. A light diffuser, placed at the end of the fiber, makes it possible to emit nondirectionally. A receiver collects the information and transmits it to an image processing device, in particular with a view to storing the image.

Abstract: The invention relates to integrated circuits comprising a set of identical differential pairs of two transistors each (T1, T2; T3, T4) one receiving a variable voltage (Vinp, Vinn) at its base and the other receiving a fixed reference voltage (Vrefp, Vrefn). In order to reduce the dispersion of the offset voltages of said differential pairs, it is provided that the transistor (T2, T4) that receives a fixed reference voltage has an emitter surface at least twice as large as the transistor (T1, T3) that receives a variable voltage at its base. Application to signal folding circuits and to analog-to-digital converters using differential pairs of transistors.

Abstract: The invention relates to the fabrication of optical microsystems for miniature cameras or miniature matrix displays. It is proposed that N dot matrix arrays and associated circuits should be collectively fabricated, on the front of a semiconductor wafer, to produce N identical chips, with on the side of each array, external connection lands; a plate, used to collectively form N identical optical image-forming structures, each optical image-forming structure covering a respective chip and being designed to form an overall image corresponding with the whole of the matrix array of the respective chip, is fabricated collectively and placed in close contact with the front of the semiconductor wafer; through the thickness of the wafer, conductive vias extending to the contact lands are opened, and, only after these various operations, the wafer is divided into N individual optical microsystems comprising an electronic chip covered by an optical structure.